System of communication in which arbitrary groups of letters, numbers, or symbols represent units of plain text of varying length.
Sources:
CNSSI 4009-2015
from
NSTISSI No. 7002
Computer instructions and data definitions expressed in a programming language or in a form output by an assembler, compiler, or other translator.
Sources:
CNSSI 4009-2015
from
Merriam-Webster